Commit Message

The cpufreq drivers don't need to do runtime PM operations on the
virtual devices returned by dev_pm_domain_attach_by_name() and so the
virtual devices weren't shared with the callers of
dev_pm_opp_attach_genpd() earlier.
But the IO device drivers would want to do that. This patch updates the
prototype of dev_pm_opp_attach_genpd() to accept another argument to
return the pointer to the array of genpd virtual devices.
Reported-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
@Rajendra: Can you please test this one ? I have only compile tested it.
drivers/opp/core.c | 5 ++++-
include/linux/pm_opp.h | 4 ++--
2 files changed, 6 insertions(+), 3 deletions(-)

On 11-07-19, 15:09, Rajendra Nayak wrote:
> Sorry for the delay
Same here :)
> I seem to have completely missed this patch.> I just gave this a try and here are some observations,> > I have a case where I have one device with 2 power domains, one of them> is scale-able (supports perf state) and the other one supports only being> turned on and off.> > 1. In the driver I now need to use dev_pm_domain_attach_by_name/id to attach the> power domain which supports only on/off and then use dev_pm_opp_attach_genpd()> for the one which supports perf states.> > 2. My OPP table has only 1 required_opps, so the required_opp_count for the OPP table is 1.> Now if my device tree has my scale-able powerdomain at index 1 (it works if its at index 0)> then I end up with this error> > [ 2.858628] ufshcd-qcom 1d84000.ufshc: Index can't be greater than required-opp-count - 1, rpmh_pd (1 : 1)> > so it looks like a lot of the OPP core today just assumes that if a device has multiple power domains,> all of them are scale-able which isn't necessarily true.
I don't think a lot of OPP core has these problems, but maybe only
this place. I was taking care of this since the beginning just forgot
it now.
What about this over this commit:
diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index d76ead4eff4c..1f11f8c92337 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1789,13 +1789,16 @@ static void _opp_detach_genpd(struct opp_table *opp_table)
*
* This helper needs to be called once with a list of all genpd to attach.
* Otherwise the original device structure will be used instead by the OPP core.
+ *
+ * The order of entries in the names array must match the order in which
+ * "required-opps" are added in DT.
*/
struct opp_table *dev_pm_opp_attach_genpd(struct device *dev,
const char **names, struct device ***virt_devs)
{
struct opp_table *opp_table;
struct device *virt_dev;
- int index, ret = -EINVAL;
+ int index = 0, ret = -EINVAL;
const char **name = names;
opp_table = dev_pm_opp_get_opp_table(dev);
@@ -1821,14 +1824,6 @@ struct opp_table *dev_pm_opp_attach_genpd(struct device *dev,
goto unlock;
while (*name) {
- index = of_property_match_string(dev->of_node,
- "power-domain-names", *name);
- if (index < 0) {
- dev_err(dev, "Failed to find power domain: %s (%d)\n",
- *name, index);
- goto err;
- }
-
if (index >= opp_table->required_opp_count) {
dev_err(dev, "Index can't be greater than required-opp-count - 1, %s (%d : %d)\n",
*name, opp_table->required_opp_count, index);
@@ -1849,6 +1844,7 @@ struct opp_table *dev_pm_opp_attach_genpd(struct device *dev,
}
opp_table->genpd_virt_devs[index] = virt_dev;
+ index++;
name++;
}

On 7/17/2019 11:17 AM, Viresh Kumar wrote:
> On 11-07-19, 15:09, Rajendra Nayak wrote:>> Sorry for the delay> > Same here :)> >> I seem to have completely missed this patch.>> I just gave this a try and here are some observations,>>>> I have a case where I have one device with 2 power domains, one of them>> is scale-able (supports perf state) and the other one supports only being>> turned on and off.>>>> 1. In the driver I now need to use dev_pm_domain_attach_by_name/id to attach the>> power domain which supports only on/off and then use dev_pm_opp_attach_genpd()>> for the one which supports perf states.>>>> 2. My OPP table has only 1 required_opps, so the required_opp_count for the OPP table is 1.>> Now if my device tree has my scale-able powerdomain at index 1 (it works if its at index 0)>> then I end up with this error>>>> [ 2.858628] ufshcd-qcom 1d84000.ufshc: Index can't be greater than required-opp-count - 1, rpmh_pd (1 : 1)>>>> so it looks like a lot of the OPP core today just assumes that if a device has multiple power domains,>> all of them are scale-able which isn't necessarily true.> > I don't think a lot of OPP core has these problems, but maybe only> this place. I was taking care of this since the beginning just forgot> it now.> > What about this over this commit:
Yes, this does seem to fix my concern mentioned in 2. above.
> > diff --git a/drivers/opp/core.c b/drivers/opp/core.c> index d76ead4eff4c..1f11f8c92337 100644> --- a/drivers/opp/core.c> +++ b/drivers/opp/core.c> @@ -1789,13 +1789,16 @@ static void _opp_detach_genpd(struct opp_table *opp_table)> *> * This helper needs to be called once with a list of all genpd to attach.> * Otherwise the original device structure will be used instead by the OPP core.> + *> + * The order of entries in the names array must match the order in which> + * "required-opps" are added in DT.> */> struct opp_table *dev_pm_opp_attach_genpd(struct device *dev,> const char **names, struct device ***virt_devs)> {> struct opp_table *opp_table;> struct device *virt_dev;> - int index, ret = -EINVAL;> + int index = 0, ret = -EINVAL;> const char **name = names;> > opp_table = dev_pm_opp_get_opp_table(dev);> @@ -1821,14 +1824,6 @@ struct opp_table *dev_pm_opp_attach_genpd(struct device *dev,> goto unlock;> > while (*name) {> - index = of_property_match_string(dev->of_node,> - "power-domain-names", *name);> - if (index < 0) {> - dev_err(dev, "Failed to find power domain: %s (%d)\n",> - *name, index);> - goto err;> - }> -> if (index >= opp_table->required_opp_count) {> dev_err(dev, "Index can't be greater than required-opp-count - 1, %s (%d : %d)\n",> *name, opp_table->required_opp_count, index);> @@ -1849,6 +1844,7 @@ struct opp_table *dev_pm_opp_attach_genpd(struct device *dev,> }> > opp_table->genpd_virt_devs[index] = virt_dev;> + index++;> name++;> }> >

On 17-07-19, 15:34, Rajendra Nayak wrote:
> > > On 7/17/2019 11:17 AM, Viresh Kumar wrote:> > On 11-07-19, 15:09, Rajendra Nayak wrote:> > > Sorry for the delay> > > > Same here :)> > > > > I seem to have completely missed this patch.> > > I just gave this a try and here are some observations,> > > > > > I have a case where I have one device with 2 power domains, one of them> > > is scale-able (supports perf state) and the other one supports only being> > > turned on and off.> > > > > > 1. In the driver I now need to use dev_pm_domain_attach_by_name/id to attach the> > > power domain which supports only on/off and then use dev_pm_opp_attach_genpd()> > > for the one which supports perf states.> > > > > > 2. My OPP table has only 1 required_opps, so the required_opp_count for the OPP table is 1.> > > Now if my device tree has my scale-able powerdomain at index 1 (it works if its at index 0)> > > then I end up with this error> > > > > > [ 2.858628] ufshcd-qcom 1d84000.ufshc: Index can't be greater than required-opp-count - 1, rpmh_pd (1 : 1)> > > > > > so it looks like a lot of the OPP core today just assumes that if a device has multiple power domains,> > > all of them are scale-able which isn't necessarily true.> > > > I don't think a lot of OPP core has these problems, but maybe only> > this place. I was taking care of this since the beginning just forgot> > it now.> > > > What about this over this commit:> > Yes, this does seem to fix my concern mentioned in 2. above.
Great. I will include your Tested-by:, Lemme know if you have any
objections.